PROCESS FOR PRODUCING CYSTEINE DERIVATIVES

摘要

A process for producing cysteine derivatives having especially high optical purities economically advantageously at a high production efficiency even on an industrial scale. The process for producing cysteine derivatives represented by general formula (III) (wherein R<0> represents hydrogen or an amino-protecting group like R<1>; R<1> represents an amino-protecting group; R<2> represents a carboxyl-protecting group; and R<3> represents C1-7 alkyl, C6-10 aryl, or C7-10 aralkyl) is one which comprises reacting an amino acid derivative represented by general formula (I) (wherein R<1>, R<0>, and R<2> are each as defined above; and X represents a leaving group) with a thiol compound represented by general formula (II) (wherein R<3> is as defined above), wherein the reaction is conducted in an organic raction medium in the presence of a base and water.